Fort adapter for front end loader

ABSTRACT

A fork adapter for attachment to the bottom plate of the scoop of a front end loader comprising a linearly extending tubular support member having a tubular post extending from the rear portion thereof. A frame comprises a pair of L-shaped plates each having a first leg extending upwardly along the sides of said support member and post and a second leg extending rearwardly, with a nut between the second legs above the support member. A screw in the nut has a swivel base on its lower end and a handle on its upper end. The post is open at the top, to receive an extension piece therein, such as lumber of conventional size. At its rear, the tubular support member has an end plate which extends above the upper surface thereof.

Unite States atent Duffield 1 1 Sept. 30, 1975 1 FORT ADAPTER FOR FRONT END LOADER Primary E.\'aminerR0bert R. Song [75] Inventor: Cedric A. Duffield, Greencastle, Pa. Fm" lrvm Lavme {73] Assignee: Greencastle Metal Works,

Greencastlc, Pa. [57] ABSTRACT [22] Filed Apr 3 1974 A fork adapter for attachment to the bottom plate of Appl. No; 457,328

the scoop of a front end loader comprising a linearly extending tubular support-member having a tubular post extending from the rear portion thereof. A frame comprises a pair of L-shaped plates each having a first leg extending upwardly along the sides of said support member and post and a second leg extending rearwardly, with a nut between the second legs above the support member. A screw in the nut has a swivel base on its lower end and a handle on its upper end. The post is open at the top, to receive an extension piece therein, such as lumber of conventional size. At its rear, the tubular support member has an end plate which extends above the upper surface thereof.

10 Claims, 3 Drawing Figures US. Patent Sept. 30,1975 3,908,844

FORT ADAPTER FOR FRONT END LOADER BACKGROUND OF THE INVENTION The present invention relates to a fork adapter for attachment to the bucket of a front end loader, so that the front end loader may handle material carried on pallets, carried in boxes, or bound together by straps.

A number of suggestions have been advanced in the prior art for attachments in the nature of forks to be secured to the scoops of front end loaders and similar earth working machines. These have fallen into several different categories, all of which have deficiencies, as pointed out hereinbelow.

In some fork lift adapters or attachments, it was necessary to modify the scoop, as by providing holes through the side walls, and then securing the fork to the scoop by bolts; in some cases, brackets or support arms were secured to the side walls of the scoop, to which the fork lift attachment was secured by bolts or the like.

In other suggestions, the pair of forks were joined by a transverse bar which was received in a bracket attached to the scoop, as a modification thereof. Such a construction required not only modification of the scoop, but also required a relatively large assemblage of a pair of forks and a transverse connecting bar.

A further suggestion in the prior art provided a fork lift attachment for earth moving equipment including a bucket having a pair of pivoted portions which were activated so as to secure the attachment by clamping a portion of it between the two parts of the bucket. It is apparent that such an. attachment could only be used where the earth working machine was provided with such a specialized bucket, and could not be used where the machine was equipped only with a conventional scoop.

A further proposal has been made in which simple forks were attached to the bottom plate of a scoop by clamping screws. This construction was made of steel stock, and required multiple screws for each fork in order to secure the fork to the scoop, and prevent movement in a lateral or pivoting direction. A significant amount of machining was required to produce this fork, thereby making it more expensive than desirable.

SUMMARY OF THE INVENTION The present invention provides a fork adapter which may be readily clamped to the bottom plate of the bucket of a front end loader. The fork adapter comprises a lineraly extending tubular support member, preferably of rectangular cross section. A tubular post of the same structural tubular material as the support member is secured to the support member, extending from the upper surface thereof, and attached to the support member at the rear portion thereof, but spaced from its rear end. The transverse width of the post is less than the transverse width of the support member. A frame is provided comprising a pair of L-shaped plates. Each of these plates has a first leg extending vertically, with the lower portion thereof engaging the side of the support member, and thence extending upwardly so that the upper portion thereof engages the side of the post: the upper and lower portions are offset, providing additional strength. A second leg, integral with the first leg extends rearwardly, and these second legs have between them a nut, the nut thereby being supported above the upper surface of the support member.

A screw is threaded into the nut, having a swivel base on its lower end, and a handle on its upper end, so that it may be rotated to thereby clamp the fork adapter to the lower plate of the scoop. Extensions are provided on the first legs of the frame plates, extending forwardly and rearwardly along and secured to the sides of the support member, thereby giving added strength. In addition, a reinforcing member is carried within the support member, underlying the post and extending forwardly and rearwardly thereof. The post is open at its upper end, and may receive an extension member, of conventional lumber. In addition, the rear of the support member is provided with an upstanding plate which extends above the upper surface of the support member, thereby serving to engage the lower surface of the bottom plate of the scoop of the front end loader, to provide secure attachment without danger of displacement.

Among the objects of the present invention are to provide a fork adapter which is strong, while being of light weight.

Another object of the present invention is the provi- I sion of a fork adapter which is of economical construction, being made of readily available materials, assembled by conventional welding techniques, and requiring no expensive machining.

Yet another object of the present invention is to provide a fork adapter which may be readily attached to the conventional scoop of a front end loader.

A still further object of the present invention is the provision of a adapter which has only a simple singleelement clamp construction, but which will be securely attached to the scoop of a front end loader.

Other objects and many of the attendant advantages of the present invention will be readily understood from the following specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a part of a front end loader with fork adapters in accordance with the present invention attached thereto.

FIG. 2 is an enlarged perspective view of the fork adapter shown in FIG. 1. 1

FIG. 3 is a cross-sectional view taken on the line 33 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, wherein like or corresponding reference numerals are used for like or corresponding parts throughout the several views, there is shown in FIG. I a conventional front end loader, generally designated 10, and including lift arms 11 and power cylinders 12 for rotating the scoop 13 about the ends of the arms 11. The scoop 13 is of generally conventional construction, and includes side plates 14 and a bottom 15. A pair of identical fork adapters 20, in accordance with the present invention, are shown secured to the bottom plate 15, the fork adapters 20 carrying extension posts 21.

Referring now to FIG. 2, the fork adapter 20 may be seen to comprise a linearly extending tubular support member 25, preferably made of conventional and readily available structural tubing having a nominal outside dimension of two inches by four inches. In its preferred form, the support 25 has a length of approximately 6 feet.

A post 30 is provided, prefereably made of the same structural tubular material as the support member 25. Post 30 extends from and is secured to the upper surface of the support member 25, and while the transverse dimension of the tubular support 25 is approximately 4 inches, the post 30 has a transverse dimension of approximately 2 inches, extending forwardly and rearwardly approximately four inches. As shown, the upper end of the post 30 is uncapped, or left open, and conventional lumber, such as so-called two inch by four inch lumber may be readily inserted in the post 30, to thereby provide the extension post 21.

A reinforcing and strengthening plate 31 of generally triangular configuration is secured to the front face of post 30, and also to the tubular support 25. Within the tubular support 25 there is a tubular reinforcing member 35 (see also FIG. 3) which extends beneath post 30, and forwardly and rearwardly thereof. The reinforcing member 35 may be secured in position by any suitable means.

A frame generally designated 40 is provided for additionally securing the post 30 to the support member 25, and to support a part of the clamping structure, as hereinbelow set forth. The frame 40 comprises a pair of plates 41 and 42 (see FIG. 3). The plates 41 and 42 are preferably of a generally L-shape, having a first upper leg portion 43A extending along and secured to the post 30, and a lower leg portion 438 extending along the side of the support 25. The lower portion 43B may have a forward extension 43C and a rear extension 43D also extending along the side of the support 25. A second leg 46 of the frame plate 41 extends rearwardly of the post 30, being above the upper surface of the support member 25. As is apparent from FIG. 3 in particular, the lower portion 43B of the first leg is offset from the upper portion 43A of the first leg, these portions being integral and joined by a connecting bend 43E.

Between the two rearwardly extending legs of the two plates 41 and 42 is a nut 50, secured thereto as by welding. The axis of nut 50 is generally perpendicular to the support member 25. A screw 51 is threaded in the nut 50, andcarries at its lower end a swivelly connected base 52, while at its upper end the screw 51 is provided with a handle 53.

At its rear end, the tubular support member 25 is provided with a plate 26, secured thereto as by welding, which extends somewhat above the rear upper surface of the support member 25. The upper surface of the plate 26 engages the lower surface of the bottom plate of the scoop of the front end loader, and this lower surface of the scoop bottom plate is also engaged by the portion of the upper surface of the support member 25 which underlies the screw 51 and swivel base 52. As will be apparent, the portion of the upper surface of support member 25 which is forward of and adjacent to the end plate 26 is maintained spaced from the bottom surface of the scoop bottom plate.

In its preferred embodiment, the fork adapter 20 has a length of about 6 feet, with the post 30 having a height of about one foot, and being spaced about 2 feet from the rear of the support member 25. The completed device may be readily handled by one or two men, since it weighs only approximately 85 pounds, while being able to support 1,500 pounds. In addition, tests have shown that each fork is capable of lifting 2,200 pounds carried two feet forwardly of the post 30.

Hence, the fork adapter 20 has relatively great strength while being of relatively low weight.

In use, the fork adapters 20 are positioned on the ground, or other supporting surface, and the screw 51 is turned so as to provide a suitably large space between the swivel base 52 and the upper surface of the support member 25. The front end loader machine and the scoop 13 are manipulated so as to insert the front edge of the bottom plate into the space provided, and then the handle 53 is rotated so as to provide a clamping engagement of the adapter on the scoop 13. Alternatively, if necessary, the adapter 20 may be lifted and placed on the scoop 13. The extension posts 21 may then be placed in the hollow post 30, so that relatively high loads may be carried conveniently, with the scoop 13 tilted somewhat so that the support members are inclined to the horizontal.

The fork adapter 20 is characterized by both economy and strength. The strength of the fork adapter 20 resists bending of the support 25 due to loads carried on the upper surface of support 25, which loads would tend to cause the front end of support member 25 to be lower than the portion thereof beneath the post 30. The post contributes to the strength of the clamping attachment including the nut 50 and screw 51, and the reinforcing member as well as the extensions 43C and 43D all contribute to additional strength at the point of concentration of forces, which generally underlies the post 30. Further, the offsetting of the upper portion 43A and lower portion 43B also contributes to the strength of the adapter 20, providing additional strength against breakage of the adapter 20, as by separation of either or both of the posts 30 and frame from the support member 25.

Security of engagement of the fork adapter 20 on the bottom plate 15 is enhanced by the plate 26, the upper edge of which has concentrated area engagement with the bottom of the bottom plate 15. This increases the frictional contact with the bottom of the bottom plate 15, and together with the fact that the rear of the post 30 engages the front edge of the plate 15 prevents any turning or rotation of the adapter 20 on the bottom plate 15.

While loads on forks adapters are generally considered to bend the front end of the fork adapter downwardly, there have been encountered instances in which the fork adapters have been stressed in the opposite direction, due to operators of the front end loaders attempting to force the front ends or front portions of the fork adapters into the ground, either to be able to insert the fork adapters under a load, or to remove the fork adapters from beneath a load which has been lifted, for example, from a truck, and then placed on the ground. The weight of such loads is still carried by the support members 25, and the operators, in attempting to release the fork adapters from the load cause the scoop 13 to be rotated so that the front ends of the support members 25 are tended to be lowered, while the rear ends thereof are tended to be raised. This places an unconventional stress on the fork adapters, which stress is suitably resisted by the hereinabove noted constructional features provided.

There has been provided a fork adapter which is of great strength, capable of handling both normal lift loads, and reverse loads placed thereon. The fork adapter herein disclosed is of economical and light weight construction, being readily fabricated by conventional welding techniques from such readily available material as structural tubing. The fork adapter of the present invention has provision for ready and economical vertical extension of the posts thereof, while being readily attached to a conventional scoop of a front end loader, with security and economy of time.

It will be obvious to those skilled in the art that various changes may be made without departing from the spirit of the invention and therefore the invention is not limited to what is shown in the drawings and described in the specification but only as indicated in the appended claims.

I claim:

1. A fork adapter for the bucket of a front end loader comprising:

a linearly extending support member,

an upright post secured to said support member at the rear portion thereof and extending substantially perpendicularly thereto,

a frame comprising a pair of L-shaped plates on opposite sides of said support member and post, each having a first leg extending along a side of said support member and secured thereto and thence upwardly along and secured to a side of said post, each said frame plate further comprising a second leg extending rearwardly and above said support member,

a nut secured between said second legs with the axis thereof generally perpendicular to said support member, a screw in said nut, and a handle at the upper end of said screw,

whereby said frame strengthens the attachment of said post to said support member and supports said nut and screw.

2. The fork adapter of claim 1, said linearly extending support member having an upstanding plate at the rear end thereof extending above the upper surface of said support member.

3. The fork adapter of claim 1, wherein said upstanding post is a hollow tubular member open at the upper end thereof.

4. The fork adapter of claim 1, said support member being a hollow tubular member, and a reinforcing member therein beneath said post and extending forwardly and rearwardly of said post.

5. The fork adapter of claim 1, said post having a lesser transverse width than said support member.

6. The fork adapter of claim 5, wherein said frame plate first legs have the upper portions thereof along said post offset from the lower portions thereof along said support member.

7. The fork adapter of claim 6, wherein said first legs have extension means extending along and secured to the sides of said support members.

8. The fork adapter of claim 7, said extension means extending forwardly and rearwardly of said post.

9. The fork adapter of claim 8, said support member being a hollow tubular member, and a reinforcing member therein beneath said post and extending forwardly and rearwardly of said post.

10. The fork adapter of claim 1, wherein said support member and said post are hollow tubular members. 

1. A fork adapter for the bucket of a front end loader comprising: a linearly extending support member, an upright post secured to said support member at the rear portion thereof and extending substantially perpendicularly thereto, a frame comprising a pair of L-shaped plates on opposite sides of said support member and post, each having a first leg extending along a side of said support member and secured thereto and thence upwardly along and secured to a side of said post, each said frame plate further comprising a second leg extending rearwardly and above said support member, a nut secured between said second legs with the axis thereof generally perpendicular to said support member, a screw in saiD nut, and a handle at the upper end of said screw, whereby said frame strengthens the attachment of said post to said support member and supports said nut and screw.
 2. The fork adapter of claim 1, said linearly extending support member having an upstanding plate at the rear end thereof extending above the upper surface of said support member.
 3. The fork adapter of claim 1, wherein said upstanding post is a hollow tubular member open at the upper end thereof.
 4. The fork adapter of claim 1, said support member being a hollow tubular member, and a reinforcing member therein beneath said post and extending forwardly and rearwardly of said post.
 5. The fork adapter of claim 1, said post having a lesser transverse width than said support member.
 6. The fork adapter of claim 5, wherein said frame plate first legs have the upper portions thereof along said post offset from the lower portions thereof along said support member.
 7. The fork adapter of claim 6, wherein said first legs have extension means extending along and secured to the sides of said support members.
 8. The fork adapter of claim 7, said extension means extending forwardly and rearwardly of said post.
 9. The fork adapter of claim 8, said support member being a hollow tubular member, and a reinforcing member therein beneath said post and extending forwardly and rearwardly of said post.
 10. The fork adapter of claim 1, wherein said support member and said post are hollow tubular members. 